Hydraulic oscillator



Oct. 7, 1941. L. F. MOODY 2,258,464

HYDRAULIC OSCILLATOR Filed March 29, 1938 4 Sheets- Sheet l H L} L E 38 I 41' I I l I I Q a; I I 49 l 50 a I 40 I I INVENTOR [5/ 5/ LEwls F. Moouv qg g AT ORNEY HYDRAULIC OSCILLATOR Filed March 29, 1938 4 Sheets-Sheet 2 INVENTOR LEWIS F. MoonY A TORNEY i 2s 27 w Filed March 29, 1958 4 Sheets-Sheet 3 LEWIS F. MoouY ATTORNEY Oct. 7, 1941,.

L. F. MOODY HYDRAULIC OSCILLATOR Filed March 29, 1938 4 SheetS-Sheet 4 INVENTOR LEwls F PIoonv l w I;

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VIIII ml A TORNEY Patented Oct. 7, 1941 I 2,258,464 HYDRAULIC OSCILLATOR Lewis Ferry Moody, PrincetomN. J. Application March 29, 1938, Serial No. 198,792

18 Claims. (01. 114-125) t This-invention relates to a device for settingu an oscillating or reciprocating motion in a column of fluid contained in a conduit connecting two reservoirs, and maintaining this oscillatingmotion against opposing forces such as friction or-fluid resistances and any external force tending to oppose the oscillation. The use of the device is illustrated in connection with 'a system of ship stabilization, or anti-rolling installation. Another possible application is the use of two of the devices such as described ior the hydraulic transmission of power.

The device cannot be properly termed either a pump-or a turbine, since its purpose and functionar definitely differentiated from either. A pump delivers fluid in a single direction against a "continuously opposing head, and its operation results in the delivery oi fluid which never again passes through the machine; that is, there is a net quantity of fluid transferred from a sump to a point of delivery, at the expense of a continuous expenditureof power. In a turbine, fluid is passed in a single direction, under head, through the machine, with a net transfer of fluid from a reservoir to 'a tail-race, and with continuous delivery of powerto a driven machine. The present device, in contrast, entails no net quantityof fluid either pumped or allowed to pass inone directionof flow; all the fluid passing in one direction subsequently news back in the opposite direction in a cyclic action continuously recurring, and there is an alternating expenditure and delivery'of power from and by the hydraulic portion of the device to or from .the electric generator-motor to which it is connected. While the object of a pump or turbine is thecont-inuous delivery of fluid against a head or utilization of a flow of fluid under head, in this invention the head produced by the machine; at certain points'in the cycle of operation,is an acceleration head imparted to the flow to accelerate'itsvelocity; and at other points of the cycle a deceleration head, tending to cause a certain rate of retardation of the fluid flow, is abstracted from the fluid energy. The amount of this acceleration head is expressed mathematically by i g dt inwhich L is the equivalent length of the conduit, g the acceleration of gravity,]and

. dt isthe derivative of the'equivalent velocity of flow with respect to time. The purposesand mode of operation will be best understood from the following description of specific applications, as illustrated in the following figures:

Fig. 1 is a diagrammatic sketch representing a cross-section, on line |I of Fig. 2, of a' ship; illustrating the use of the stabilizing systemy v Fig. 2 is a diagrammatic sketch representing a plan 'view of a portionof the ship of Fig. 1;

Fig. 3 is a section of the hydraulic oscillator unit, on line 3-3 of Fig. 4, showing wthe hy draulic portion of the'device, in a meridian plane;

or plane containing the axis of rotation;

Fig. 4 is a transverse section of the oscillator in plane 44 of Fig. 3, being a view looking down on the runner or revolving hydraulic elementf Fig. 5 is an enlarged cylindrical section on line 5-5 of Fig. 4, developed, or unrolled on a plane,

showingthe relation and formation of the fixed vanes and rotating blades;

' Fig. 6 is a continuation, to a somewhat larger scale, of Fig. 3,'showing the upper portion of the oscillator device, including the upper-fixed vanes, the power shaft, blade operating cylinder, control valve, reduction gears and electric generator mo-tor;' I Fig. 7 is an enlarged view of the runner in meridian section, or section containing the axis of rotation, along lines L -T of Fig. 8, showing the blade-adjusting mechanism Within the hub;

Fig. 3 is a transverse section through the runner hub on line 8-8 of Fig.1; .1 Fig. 9: is an enlarged section of the controlvalve, the details of which were omitted in Fig. 6. Before describing theoscillator unit itself, its application to ship stabilization will first be ex; plained. Referring to Figs. 1 and 2, I and 2 are ballast tanks or bilge tanks located at each side of the ship at or near the midship section, 0011- nected by the crosspipes 3 and 4 along the bottom of the ship. These cross-pipesare con nected to' the tanks by the vertical pipes or cas-l ings 5 and 6, preferably of gradually tapering form as shown. r

Within the pipe or casing 5 is the revolving runner I of a hydraulic oscillator, shown dotted connected by a vertical power shaft 8 to a reduction gear and electric generator-motor 9 mounted on top of tank 'I. On the right-hand side of Fig. 1, I0 indicates in dottedlines the runn'er of a second hydraulic oscillator, with its shaft H and generator-motor l2. These'are behind the plane of Fig. l, and runner Wis not within the vertical section of pipe'3, but within the corresponding section of pipe 4, thegeneratonm'otor being lo-Z invention in a ship.

cated at l2 in Fig. 2. Thus each cross-pipe such as 3 and 4 has one oscillator unit at one side, that for pipe 3 being at 9 and the one for pipe 4 being at l2, in Fig. 2. By thus staggering or alternating the units, the weights on both sides of the ship are equalized. Other pairs of units similarly arranged can be added along the length of the ship to give the desired stabilizing capacity. When unit 'l--9 is accelerating the fluid column in pipe 3. by impellingitdownward, unit I0l2 is accelerating the fluid in pipe 4 by drawing it upward, so that the two columns swing in unison, and similarly when the flow is reversed.

It will be seen from the disclosure herein that the oscillator unit is not symmetrical. about a. horizontal plane through its runner, since .in.

downward flow the fluid is passing froma tank in which the velocity is low through a generally contracting passage into a pipe of smaller section and increased velocity of flow, while for upward flow the fluid. passes through the reverse process in agenera-11y-enlargingv passage. Any resulting-lack of perfect hydraulic symmetry between upward anddownwardflow is compensated by arranging the oscillators in pairs each pair having one unit on each side ofthesh'ip and each.'acting.separate- 1y within its own conduit. The'condui-ts extending from one tank to the-other are laterally enclosed, that is the-conduits are openonly at their ends where: they. communicate with the tanks. The conduits are otherwise entirely closed aroundtheir circumference fromione tank to theother so that fluidiscompelled-to now from one'tank to thewother;

Thefluid inthe tanks and pipesmaybe fresh or sea-water or fuel oil. The action will be described for water, but will be similar with oil butwith greater hydraulic resistances due to viscosity. The tank on eachside is. common to a series of units, and each tank. can be'equipped withswash platesto limit foreand aft surging within the tank. during severe pitching of the vessel. Small pipes l3- running athwartship to interconnect the airspaces in the tanks-allow for a. displacement of air to avoid compressing the air in the tanks, and a riser pipe as at [4 may be added to maintain the air pressure at' substantially atmospheric. value;

Fig, 3 is a cross-section throughlthe axis of oneof: the oscillator units such as 5--9 of Figs. 1'

and 2, the runner denoted generally by 1 being shown solid with the front. half of thecasing removed. 5 denotes. thetapering pipe connecting to cross-pipe 3. Withinthe tapering section is a seriesof: axially directed fixed guide and stay vanes I 5' carrying a. central-fixed cone It con-- tinuous in contour withthe rotating runner hub I]. Above-the runner the casing l8- contains" a removableliner l9-.=forminga continuation of the taper pipe and: carrying .a' second series of axiallydirected fixed guide, and stay vanes 20. These vanes carry the bearing housing 2|, continuous in contour with the runner hub. Between the runner blades and each set of fix-ed vanes I 5 and 2431s a transmission'spacein which the flow merges into a. continuous ring. offluid. The casing 3 is bolted to the bottom of thetank I. The runner hub is-attached to the power shaft 8; Wherr desired a stub shaft extension may be addedbelowtherunner hub, running in'a' steady hearing: within. the conel=6,. to' give additional lateral support" for therevolving element; This is not:shown,.as'itsaddition' can be readily'understood without illustration. The liner and bearing housing |'.9.--2I would be made in halves 1 bolted together, to permit removal from the shaft; or if preferred the shaft could connect to the runner hub by a taper fit, to permit its withdrawal.

Fig. 4 is a plan view, looking down on the runner. The runner consists of the hub I! carrying the-blades 22 which are pivotally supported by it, and capable of angular movement relatively to the hub. The blade operating mechanism is carried within the hub and shaft, as shown in detail in Figs. '7 and 8.

Fig. 5 is a cylindrical section along line 5-5 of Fig. 4, unrolled or developed into a plane. It shows the relation between the runner blades 22 an'd'the fixed guide vanes l5 and 20. The direction of motion of the shaft and runner is indicated by the arrows around shaft 8 in Fig. 3, at the runner periphery in Fig. 4 and just above blade 22 in Fig, 5. Since the fluid flow alternates between upward and downward, the guide vanes l5 and 2d are symmetrical in section about a vertical central plane, to direct the flow intov the runner'or away from the runner in an-axial direction; and the sectionsare also symmetrical about a horizontal plane to give, equally good flow conditions for upward and downward flow. They are thickest in the middle, tapering to roundededges of small thickness at both ends, with smooth flow contours.

The runner blades 22 are symmetrical in section about a plane surface; the entire blade be-- ing symmetrical about a single-central plane extending from hub to-periphery. This is an essential condition since the runner is desired to operate with equal efiect when the flow is upward and the other edge 24 always being the leavingi edge. To suit this uni-directional flow along the L blade, the section is made thickest near the entrance edge, with well rounded entrance, and'is tapered gradually to a thin leaving edge to minimize the production of an eddying wake.

The runner blade is rotated with angular reciprocating motion relatively to the hub into the angular positions shown in dotted lines through an'angular range from 22 to 222, this reciprocation being continuously maintained. In mid-position, 221, the central planes of all the blades come into a single plane normal to the axis of rotation; and each blade in plan view as in Fig. 4-

is a sector, so that all the blades togethercompletely close the annular flow passage except for the clearance provided between adjacent blade edges, between the outer periphery and the pipe or casing wall, and between the inner blade periphery and the hub, these clearances being sufli'-- cient to avoid fouling or rubbing between blades, and between blades and pipe wall. In mid-position 221, the blades thus effectively close the passage against any substantial flow, and in effect act as a shut-off valve. By this means a safety feature is provided so that if at any time due tn a failure or mproper functioning of the electrical controls, the burning out of the generatormotor or other accidental cause the fluid column oscillation should reverse its proper phase in relation to the rolling of the ship, so that it would then tend to build up the rolling, or if continued to endanger overturning, an auxiliary control such as a push-button. circuit or hand switch 36' can be provided to throw the blades into midposition and to lock the fluid in thetanks. If unequally divided between the two tanks a slight list would be impart-ed to the ship until the balance is corrected, but. no augmentation of roll would ensue.

The functioning of the system for ship stabilize ing may be explained by comparing the motion of the fluid column in the cross-pipes to that of a pendulum bob. The effect is roughly like that of shifting ballast to oppose the rolling ofthe ship. If the fluid in the pipes and tanks is once set into oscillation in synchronism with, and in opposite direction to, the rolling of the ship, it is possible by proper proportioning for the fluid oscillation to maintain itself, taking energy from the rolling energyof the ship to overcome the fluid resistances, and automatically reducing the rolling to a small amount. This is the so-called passive system. Even with that method functioning properly, however, it is necessary to impose some control, to keep the oscillation in step and proper phase relations with the roll. One method employed is the use of air compressors to vary the air pressure in the tanks but this afiords only slow correction and is far from positive or fully controlled.

In the system used in this invention it is possible to build up quickly by the use of the oscillator units any required degree of oscillation and to maintain it in proper phase through an electrical control system such as developed by N. Minorsky and described for example, in his Patent 2,0l"7,072, the controls being responsive to the motion of the ship. With erratic rolling in a disturbed sea the fluid column oscillation can be quickly regulatedtand the rolling of the ship can be confined to a small amplitude.

The method of quickly creating and quickly controlling the oscillation demanded by the degree and kind of rolling experienced by the ship at any time is the use of the oscillator units here described. Comparing the motion of the fluid column to that of a pendulum bob, the pendulum on its forward swing is pulled down by gravity which at first accelerates its velocity on the downswing, then retards it on the upswing. The action of the hydraulic oscillator is somewhat similar to that of gravity in that when the fluid is higher than normal in one tank and tends to flow through the cross-pipe into the other tank under the acceleration of gravity, the oscillator runner has its blades turned so that it tends to impel the flow downward and to add an additional acceleration, tending to speed up the downward flow, taking power from the electric driving unit which is then acting as a motor, and deliverin head, effective as acceleration head, to the fluid. When the fluid column has been speeded up to its maximum velocity (corresponding to the bottom or middle of the pendulum. swing) the runner blades are in their widest o en position such as 22, Fig. 5, and are then merely threading through the flow without imparting any head. Then as the fluid begins to accumulate in the opposite tank the oscillator runner contributes a deceleration to that due to gravity, and abstracts head from the fluid motion, delivering power to the electric driving unit which new acts as a generator.

In the meantime the blades havebeen closing, and when the fluid reaches its highest level in the second tank (the top of the pendulum swing) the blades are in mid-position 221. They continue their angular movement and begin to impel the fluid upward on its return swing until it again reaches its maximum velocity, when the blades reach their greatest angle at 222 in the opposite direction. They then again begin to decelerate the flow until they reach the closed position 221 when the column is momentarily at rest, at its highest level in thefirst tank. The above cycle is then repeated continuously.

The change of level in the tanks, the flow velocity, and the angular motion of the blades are all substantially simple harmonic motions such as that of a pendulum, and can be represented by sine curves. The hydraulic oscillator in its complete cycle accelerates the flow in the downward direction and then retards it; then accelerates it in the upward direction and finally retards this motion. To do this the blades have turned on the hub from 221 to 22, back through 221 to 222, and finally return to the starting point 221' completing the cycle, which then repeats itself continuously.

Eig. 6 is a continuation of Fig. 3, to a slightly larger scale, she-wing the upper portion of the oscillator unit. The reference numerals 8 to 2! identify the parts shown in Fig. 3 which are here repeated. The power shaft ii which drives or is driven by therunner at different parts of the cycle, is connected to the reduction gear 25 which engages the pinion 26 carried by the shaft 21 of the electric generator-motor 9. This generator-motor could be directly connected to the shaft 8 if preferred, but is here gear-connected so that it can run at a higher speed with corresponding saving in weight and size, an arrangement which simplifies the connection of control valve 28, which would otherwise have to be mounted above the generatormotor. The electrical unit istermed a generatormotor because at'two points in the cycle of oper-' ation it acts as a motor supplying power to the shaft, and at two interveningpointsit acts as a generator taking power from the shaft; it runs continuously in one direction, however, at nearly constant speed. It may be a direct current, synchronous or induction machine. The motor shaft 21 carries a flywheel 29 advantageously mounted on this high-speed shaft rather than on shaft 8, which stores energy fromthe oscillator and. returns energy during each cycle and thus reduces the speed variation and fluctuation of electric current. That part of the power required to drive the runner when accelerating the fluid flow which has to be suppliedto the electric machine, over and above the energy supplied by the stored energy in-theflywheel, is taken from the electricsupply system to which the unit is connected; and at times when the runner is retarding the flow, the regenerated power leftover after theffly-wheel absorbs its store is fed back into the line as regenerated power. Naturally more power must be taken from the line than is returned to it, to supply the hydraulic, mechanical and electrical losses in the unit and in-the cross-piping and tanks. However, the-.so-called passive action of the water column during rolling of the ship tends automatically to maintain the oscillation as previously explained; only that additional amount of. power. required to build up the oscillation quickly and to correct erratic rolling is necessary for the continued driving of the hydraulic oscillator,

The valve 2Bcontrolsthe admission and discharge of oil under pressure to or from the operating cylinder 29. This cylinder is formed as an enlargement of the hollow shaft. 8, and contains the piston 39 connected to the operating rod 3|, which it moves upward and downward Within shaft 8 and thereby drives the blade operating mechanism within the runner hub. This operating cylinder and' blade operating mechanism is generally similar to that used in Kaplan or other adjustable-blade turbines.

The oil pressurefor the blade movement is obtained from a small pump and accumulator tank, not shown, supplying oil under pressure to the valve 28 through pipe 3!, the exhaust from the valve being returned to the pump through pipe 32.

The blade operating mechanism is shown in Figs. 7 and 8, which should make the mode of operation clear without detailed explanation. The operating rod 3| carries a spide1 32 connected by links 33 to the cranks 34 keyed to the blade stems 35, so that a vertical movement of rod 3| causes an angular movement of the runner blades 22. While them'echanism is generally similar to that used in adjustable-blade turbines, its purpose and mode of operation are difierent. In the turbine the blades are adjusted intermittently in varying amounts in response to load or speed changes on the unit, for the purpose of keeping the power and discharge constant at any given load. If the power demand-is steady, the mechanism remains at rest. In the oscillator unit, however, the blades are maintained in a continuous cyclic oscillating motion in order to substitute for steady flow a continuous oscillating motion of thefluid column, as described. Hence the piston 39 and the operating rod 3| are given a continuous reciprocating motion somewhat similar to that of the piston and rod of a reciprocating steam engine. The surging or oscillation of the water column hereby created is the thing which the turbine control mechanism isi'ntended to avoid.

This motion isimp'arted' by external electrical controls; responsive to the rolling motion of the ship. The method of operation of electrical control system regulating the current supplied to motor 36, is not a part of this invention. This currents acts on the small electric motor 38, Fig. 9,1which through worm and gear 31 raises and lowers the threaded valve stem 38. This stem actuates the balanced piston valve 39, 49 sliding within the floating sleeve 4!. When the stem 38 is raised, valve 39 uncovers port 42, admitting pressure oil to pipe 43 and chamber 44 from which it passes through the hollow tube 45 and passage 46 to the cylinder space below the piston 30, pushing the piston upward. The oil above the piston 30 passes through the annular space Himto chamber 48, from which it is exhausted through pipe 49, port 50 and passages to the exhaust pipe 32. Downward motion is similarly effected.

The valve contains a restoring mechanism, operating as follows: When the piston 30 moves upward as described, it pushes with it the tube 45 and the rod 52 connected to. the sleeve 4|, which is thereby raised in unison. with the piston 30. After an initial piston movement, this movement of the sleeve causes it to overtake. the valve. 39, 40 and to close theports, stopping furthermovement of thepiston until there is. another movement of the control motor 36 and valve rod 38. The action is such that the piston '30 copies the movement of control motor 36 and valve rod 38; and consequently the runner blades follow close- 13? the dictatesfofthe electrical controls without overtravel,1moving only when the control motormoves, and to a corresponding extent.

changes in details of construction and arrangement of partsmay be made by those skilled inthe art without departing from the spiritof the invention as set forth in the appended claims.

Idesireto claim:

' 1. A hydraulic oscillator for creating, maintainingor controlling an oscillating motion in 'a column of fluid 'of a stabilizing system comprising, in combination, "a uni-directional rotating shaft having 'a runner provided with a 'hub and a set of angularly' oscillatable blades pivotally mounted in said hub, a set of fixed axially directed guide vanes on each side of said runner, each of said guide vanes" being axially straight throughout its length, power means adapted to operate at time's'to' drive said shaft and at other times to b'e-driven by s'aid shaft for either direc-' tion of flow, and means for angularly oscillating the blades of said runner through an angular range extending to each side of a transverse plane normal "to' the runner axis whereby the blades are adapted for continuously reversing the direction of flow through the oscillator during said uni-directional rotation.

Y '2. The combination set forth in claim 1 further characterized in that said'powe'r means includes an electric motor and a flywheel.

'3. A hydraulic oscillator'for creating, main-' tainin or controlling an oscillating motion in a column of fluid for a stabilizing system comprising, in combination, a uni-directional rotating shaft having a runner provided with a hub and a set of angularly oscillatabl e blades pivotally mounted in said hub, a set of fixed axially di' rected guide vanes" on each side of said runner, each of said guide vanes being axially straight throughout its length, power means adapted to operate at times to drive said shaft and at other times to be driven by said shaft for either direction of flow, and means for angularly oscillating the blades of said runner through an angular range substantially equally divided by a transverse plane normal to the runner axis, each of said runner blades being ymmetrically formed with respect to a central surface which is a plane; and each of said fixed guide vanes being symmetrically formed with respect to a plane containing the runner axis, and symmetrically tapered to be equally adapted for flow in opposite direction.

4. A hydraulic oscillator for creating, maintaining or controlling an oscillating motion in a column of fluid for a stabilizing system comprising, in combination, a uni-directional rotating shaft having a runner provided with a hub and a set of angularly oscillatable blades pivotally mounted in said hub, a set of fixed axially directed guide vanes on each side of said runner, each of said guide vanes being axially straight throughout its length, power means adapted to operate at times to drive said shaft and at other times to be driven by said shaft for either direction of flow, and means for angularly oscillating the blades of said runner through an angular range substantially equally divided by a transverse plane normal to the runner axis, each of said runner blades being symmetrically formed with respect to a central surface which is a plane and formed in section for uni-directional flow relatively to the blade by being relatively thick near the entrance edge and gradually tapered to a thin leavingedge; and each of said fixed guide vanes being symmetrically formed with respect to a plane containing the runner axis, and symmetrically tapered to be equally adapted for flow in opposite directions.

5. A hydraulic oscillator for creating, maintaining or controlling an oscillating motion in a column of fluid for a stabilizing system comprisin in combination, a unidirectional rotating shaft having a runner provided with a hub and a set of angularly oscillatable blades pivotally mounted in said hub, a set of fixed axially directed guide vanes on each side of said runner, each of said guide vanes being axially straight throughout its length, power means adapted to operate at times to drive said shaft and at other times to be driven by said shaft for either direction of flow, and means for angularly oscillating the blades of said runner through an angular range substantially equally divided by a transverse plane normal to the runner axis, each of said runner blades being symmetrically formed with respect to a central surface which is a plane and formed in section for uni-directional flow relatively to the blade by being relatively thick near the entrance edge and gradually tapered to a thin leaving edge, and so mounted in the hub that the axis of oscillation is nearer to the entrance than to the leaving edge of the blade; and each of said fixed guide vanes being symmetrically formed with respect to a plane containing the runner axis, and symmetrically tapered to be equally adapted for flow in opposite directions.

6. In a ship stabilizing system, tanks disposed at each side of the ship, two laterally enclosed conduits whose minimum cross-sectional area is less than that of said tanks, each conduit comprising a cross, pipe disposed below the level of said tanks and vertical pipes connecting the cross pipe to each of said tanks, two substantially identical simultaneously operable hydraulic oscillator units each comprising power means and a vertical shaft, propeller-type runner adapted to be driven by or to drive said power means, the runner of one of said oscillator units being disposed in the vertical pipe of one of said conduits and the runner of the other oscillator unit being disposed in the vertical pipe of the other conduit, one of said runners being on one side of the ship and one on the other side in staggered relation to each other so as to cause alternating flow of fluid in said vertical pipes whereby the flow is upward through one runner and simultaneously downward through the other thereby causing the hydraulic characteristics of one unit to be compensated by the hydraulic characteristics of the other unit so as to obtain hydraulic symmetry during rollof the ship in either direction.

'7. In a ship stabilizing system, tanks disposed at each side of the ship, two laterally enclosed conduits whose minimum cross-sectional'area is less than that of said tanks, each conduit comprising a cross pipe disposed below the level of said tanks and vertical pipes connecting the cross pipe to each of said tanks, two substantially identical simultaneously operable hydraulic oscillator units each comprising power means and a vertical shaft oscillatable-blade propeller-type runner adapted to be driven by or to drive said power means, the runner of one of said oscillator units being disposed in the vertical pipe of one of said conduits and the runner of the other oscillator unit being disposed in the vertical pipe of the other conduit, one of said runners being on one side of the ship and one on the other side in staggered relation to each other so as to cause alternating flow of fluid in said vertical pipes whereby the flow is upward through one runner and simultaneously downward through the other, thereby causing the hydraulic characteristics of one unit to be compensated by the hydraulic characteristics of the other unit so as to obtain hydraulic symmetry during roll of the ship in either direction.

8. In a ship stabilizing system, tanks disposed at each side of the ship, two laterally enclosed conduits whose minimum cross-sectional area is less than that of said tanks, each conduit comprising a cross pipe disposed below the level of said tanks and vertical pipes connecting the cross pipe to each of said tanks, two substantially identical simultaneously operable hydraulic oscillator units each comprising power means and a vertical shaft propeller-type runnerladapted to be driven by or to drive said power means, the runner of one of said oscillator units being disposed in the vertical pipe of one ofsaid conduits and the runner of the other oscillator unit being disposed in the vertical pipe of the other conduit, one of said runners being on one side of the ship and one on the other side in staggered relation to each other so as to cause alternating flow of fluid in said vertical pipes whereby the fiow is upward through one runner and simultaneously downward through the other thereby causing the hydraulic characteristics of one unit to be compensated by the hydraulic characteristics of the other unit so as to obtain hydraulic symmetry during roll of the ship in either direction, and means providing an enclosed air space above the liquid in said tanks and a pipe interconnecting the air spaces.

9. A hydraulic machine for a stabilizing system comprising two series of fixed guide vanes, an unshrouded axial-flow runner disposed between said series of fixed vanes and separated therefrom by transition spaces, each of said guide vanes being axially straight throughout its length and formed symmetrically with respect to planes containing the axis of runner rotation and equally adapted to direct'the flow axially in either direction whereby the fluid flows only along axially straight lines, said runner having a hub provided with journal bearings and runner blades having shafts journalled in said bearings to allow oscillation of said blades, said blades being formed symmetrically with respect to a central plane surface, and means for angularly oscillating said blades through substantially equal angles to either side of a plane normal to the runner axis.

10. A hydraulic machine for a stabilizing system comprising two series of fixed guide vanes, an unshrouded axial-flow runner including blades between said series of fiXed vanes and separated therefrom by transition spaces,each of said guide vanes being axially directed throughout its length and formed symmetrically with respect to planes containingthe axis of runner rotation and equally adapted to direct the flow axially in either direction, said runner having a shaft and a hub supported thereon, journal bearings in said hub for rotatably supporting said runner blades therein, means for angularly oscillating said blades throughsubstantially equal angles to either side of a plane normal to the runner axis, said blade oscillating means including a piston and. cylinder rotating with said runner shaft, a valve for controlling the admission of pressure fluid to said cylinder, electrical mean for actuating said valve; a rid a restoring connection from said piston to'said valve, H

11. A hydraulic machine for a stabilizing system comprising, two series of fixed guide vanes, an unshrouded axial-flow runner including blades between said series of f xed vanes and separated therefrom by transition spaces, each of said guide vanes being axially directed throughout its length and formed symmetrically with respect to planes containing the axis of runner rotation andequally adapted to direct the flow axially in either direction, a shaft, a hub mounted on said shaft, journal bearings in said hub for rotatably supporting said runner blades, means forangu larly oscillatingsaid blades through sub- 'sta'ntially equal anglesto either side of a plane normal to the runner axis; said blade oscillating means including a piston and cylinder rotating with said runner shaft,- cooperating valve and ported elements for controlling-the admission of pressure fluid t'o-said'cylinder, movable electrical means for actuating one of'said element s, and a restoring'connectio'n from said piston to the otherof said elementsfor causing said pistonto followthe electrically-moved element, the (effective port opening of said ported element being produced by a differential motion between the actual movement of said electrical means and the movement ofsaid piston.

12: A hydraulic machine for ship stabilization comprising two series of fixed guide vanes, an unshrouded axial-flow runner between said series of fixed vanes ands'ep'arated therefrom by transition spac'es, each of said guide vanes being axially directed throughout its length and formed symmetrically with respect to planes containing the axis of runner rotation and equallyadapted to direct the flow axially in either direction, said runner having a shaft and a hub securedthereto, runner blades, journal bearings in said hub for rotatably supporting said runner blades, means for angularly oscillating said blades through substantially equal angles to either side of a plane normal to the runner axis whereby the machine acts'a't times as a pump in either direction of flow andat other nine as a turbine in either direc-' tion of fiow,'said'b'lade oscillating means includ-- ing a piston and cylinder, rotating with the run ner snares valve for controlling the admission of pressure fluid to said cylinder, an electrical motor for reversely actuating said valve, and a restoring connection from said piston to said valve. r r I 13;A hydraulic machine for a stabilizing systern comprising two series of fixed guide vanes, an imshreiiaiea axial-flow runner between said series of fixed vanes and separated therefrom by transition spaces, said guide vanes being formed sym metrically with respect toplanes containing the axis of runner rotationandequally adaptedto direct the flow axially in either direction, said runnerincluding a hub having journal bearings and blades rotatably s'upportedin said bearings; a shaft upon which said hub is mounted, means for angularly oscillating said blades through substantially equal angles. to either. side of a plane normal to the runner axis; said blade oscillating means including a piston and cylinder rotatable with said runner shaft, mechanism for controlling operation of said oscillating means including avalve anda ported floating sleeve cooper ating with saidvalve for controlling admission or pressure fluid to saidcylinder, electricalactuating meanslfo'rmoving; said valve to effect opera an {if said piston and thereby adjust said runner blades; and a restoring connection from said piston to said floating sleeve for causing said piston to follow-the valve movement. v,

14. A hydraulic machine fora stabilizing system comprising two series of fixed guide vanes, an unshrouded axial-flow runner including blades between said series of fixed varies and separated therefrom by transition spaces, each of said guide vanes being formed symmetrically respect to planes containing the' axis of runner rotation and equallyadaptd to direct the flow axially in either direction, and each of said runner blades being formed symmetrically with respect to a central plane surface, said-runner having a hub, journal bearings in said hub for rotatably supportin said biades therein, and means for angularly oscillating said bladesfrom one side to the other of a plane normal to the runner axisso that said machine functions at one timeas a pump in either direction of flow and at another time as a turbine in either direction or now. l

15. A hydraulic machine fora stabilizing system comprising two seriesof fixed guid'e'van'es, an unsnrouded axial-flo runner including blades between said series of fixed vanes and separated therefrom by transition spaces, each or said guide vanes being formed symmetrically with respect to plane's containing the axis of runner rotation and equally adapted to dire-ct the flow axially in either direction, and each of said runner blades being formed symmetrically with respect to a central plane surface, said runner having a hub; journal b'earings'iri said hub for r'o'tatably supporting said blades, means forming a flow passage in which said runner is disposed, means for angularly oscillating said blades from one side to the other or a plane normal to the runner axis; said runner blades being formed symmetrically with respect to a central plane surface whereby said blades when turned into a plane normal to the runner axis substantially fill the transverse area of the flow passageoccupi'ed by said runner so that in that position the blades are adapted to constitute a stop valve substantially preventing flow.

16; A hydraulic oscillator for creating, main raining or controlling an oscillating motion in a column of fluid of a stabilizing system, comprising, in combination, a runner and shaft therefor having uni-directio'nal rotation, a'set of angu larly oscillatable blades pivotally mounted'i'n said runner, a set of fixed axially directedguide vanes on each side of said runner, each of said guide vanes being axially straight throughout its length, power means adapted to drive said shaft and at other times to be driven by said shaft for either direction offlow in a continually recurring cycle, and means for angularly oscillating the blades of said runner from one' side to the other of a transverse plane normal to the runner axis;

1'7. In a ship stabilizing system, two tanks located respectively at each side of the ship; a: crosspipe disposed below the level ofsaid tanks; vertical conduits connecting said cross pipe to each of said tanks, and a single hydraulic oscil lator unit comprising power means and a vertical shaft oscillatableblad-e propeller-type runner located in on'e of saidvertical conduits to be driven by or for driving said power means so as to be adapted to cause an alternating fl'oW of fluid in said-cross pipe. v

18. In a shipstabilizing system, two-tanks-with one disposed at each side ofthe ship, two-cr'osspipes dispbs d below the level of'said-taliks; vertical conduits connecting said cross pipes to said tanks and two substantially identical hydraulic oscillator units each comprising power means and a vertical shaft propeller type runner adapted to be driven by or to drive said power means and to cause alternative fluid fiow between said tanks, said oscillator units being respectively located adjacent each tank and arranged in staggered relation by having one of the units disposed in one of said vertical conduits and the other disposed in the other vertical conduit, the portion of each conduit above its runner having a passage 

